Evaluation of three hormonal protocols for anovulatory lactating cows under regulations restricting the use of estrogenic compounds

When European Union regulations restricted the use of estrogenic compounds in food‐producing animals, refined hormonal protocols were no longer applicable for anovulatory cows. However, Ovsynch and its adaptations are routinely and uniformly applied to all cows regardless of ovarian function. To evaluate their efficacy on anovulatory cows, 143, 147 and 144 anovulatory cows received Ovsynch, Presynch and G6G protocols, respectively. In comparison, 150 cyclic cows were bred without using a synchronized protocol. Results showed that cows in the Presynch group had luteolysis responding to the last prostaglandin F_2α (PGF_2α) injection greater than the Ovsynch group. The serous progesterone levels at the first gonadotropin‐releasing hormone of Ovsych and the last PGF_2α injection was greater in the G6G group than the other two hormonal treatment groups. Concentrations of Ca²⁺ and total protein in cervical mucus in all three hormone‐treated groups before artificial insemination (AI) were significantly different from the controls. The G6G group obtained a greater pregnancy rate compared with Ovsynch and Presynch, but significantly less than the controls. For open cows in the Ovsynch group, estrus rate within 24 days after the first AI was significantly less than the controls. In conclusion, the G6G treatment resulted to better reproductive performance in anovulatory cows.     

Partial replacement of fishmeal with Clostridium autoethanogenum single‐cell protein in the diet for juvenile black sea bream (Acanthopagrus schlegelii)

Clostridium autoethanogenum protein (CAP) is a single‐cell protein derived from ethanol production and may have potential to become a substitute for fishmeal in aquafeeds. A 70‐day feeding trial was conducted with black sea bream (Acanthopagrus schlegelii) (mean initial weight 6.03 ± 0.09 g) to evaluate partial replacement of fishmeal with CAP in diets. Seven isonitrogenous and isoenergetic diets were formulated with graded levels of CAP (0, 4.85, 9.70, 14.55, 19.40, 38.80 and 58.20%) to replace fishmeal. The inclusion of CAP at all dietary levels tested did not significantly affect the growth performance (p > .05). Fish fed the CAP58.20% diet showed a significantly lower feeding rate, with significantly higher protein efficiency ratio and feed efficiency ratio compared with fish fed the other diets (p < .05). No statistical differences were found in dorsal muscle and whole‐body compositions. Total superoxide dismutase in serum of fish fed CAP58.20% diet was significantly lower compared with that of the control. Malondialdehyde, catalase, total antioxidant capacity and digestive enzyme activities revealed no significant differences among dietary treatments. Phosphorus retention efficiency significantly increased, and phosphorus discharge showed a downward trend with increasing CAP inclusion levels. In conclusion, the results indicated that CAP is a safe and effective alternative protein source, which can replace fishmeal in the diet of black sea bream up to 58.20%, without adverse effects on growth performance, antioxidation and digestive enzyme activity. This study has shown the potential of converting industrial waste into a high protein feed ingredient for aquafeeds.     

Pharmacokinetics and preliminary safety data of a single oral dose of bosentan,a dual endothelin receptor antagonist,in cats

The objective of this study was to evaluate the pharmacokinetic properties and adverse effect profile of single‐dose oral bosentan, a dual endothelin receptor antagonist, in healthy cats. Pharmacokinetic parameters were determined following a single mean ± SD oral dose of 3.2 ± 0.6 mg/kg of bosentan in 6 adult cats. Blood was collected for quantification of bosentan via high‐performance liquid chromatography with ultraviolet detection. Blood and urine were evaluated for CBC, plasma biochemical profile, and urinalysis, and repeat physical examinations were performed to evaluate for adverse effects. The mean terminal half‐life of bosentan was 20.4 ± 17.2 h. The mean peak plasma concentration was 0.49 ± 0.24 g/mL, and the mean time to maximum plasma concentration was 6.8 ± 8.6 h. The area under the curve was 5.14 ± 3.81 h·μg/mL. Oral bosentan tablets were absorbed in cats, and no clinically important adverse events were noted. Further evaluation of repeat dosing, investigation into the in vivo efficacy of decreasing endothelin‐1 concentrations in cats, as well as safety in conjunction with other medications is warranted.